Princes Anne and her husband Mark Philips were also at the birthday celebration, but arrived late due to snow. And thus missed the picture.
I don't think you should read too much into the seating arrangement, this was an informal seating.
--Previous Message-- : --Previous Message-- : : Could Lady Shakerley have been representing : Queen Elizabeth and the Duke of Edinburgh? : : She is a private friend of the Norwegian : royals, so I don't think she represented : anyone but herself. :